Five Cities That Are Leading the Way in Urban Innovation In an era of urbanization, Singapore, Houston and Medellín, Colombia, are among those redefining what cities can be As part of Singapore’s efforts to maximize scarce resources, these Supertree sculptures in a park collect rainwater. PHOTO: JOHN S. LANDER/GETTY IMAGES By MICHAEL TOTTY Updated April 21, 2016 3:00 p.m. ET 10 COMMENTS Cities are the future. In 2008, for the first time in history , more human beings lived in cities than in rural areas. The United Nations projects that by 2050 nearly two-thirds of the world’s projected 9.7 billion people will be urban. JOURNAL REPORT Insights from The Experts Read more at WSJ.com/LeadershipReport MORE IN THE FUTURE OF CITIES Singapore’s Vision of the ‘Smart City’ Autonomous Cars: Urban Misfit? Dubai’s Bold Transformation Can Suburbs Be the New Cities? Cities Dig Deep to Manage Growth Some urban planners scratch their heads